A primary goal in the harvesting of hay or forage is to dry the hay as soon as possible and then to remove it from direct exposure to sunlight. The hay must be dried before storage to avoid the problems of mold and spontaneous combustion. Exposing the cut hay to sunlight longer than is required to adequately dry it, however, can result in unacceptable loss of nutritive value of the hay due to deterioration of the protein level.
Typically, hay is harvested into approximately five-foot swaths along the ground, and is exposed to sunlight for the initial stage of the drying process. These swaths spread out the hay to maximize exposure to the sun and air to speed initial drying. The swaths of hay are then raked into narrow windrows to remove most of the hay from direct contact with the moist ground. The windrow enhances air circulation within the hay, thereby hastening the drying process. Raking hay into windrows also facilitates gathering of hay by providing rows of forage for a hay baler or other harvesting device to follow.
Many types of wheel rakes have existed for decades. Wheel rakes utilize angled, tined “pinwheels” that are propelled across the ground of a field of cut forage. Contact with the ground while traveling across the ground rotates the wheels and thereby rakes the hay in a desired direction. Of particular interest are V-rakes in which at least two banks of rake wheels are deployed in the shape of a V during operation. Generally, V-rakes employ an arm on each side of a frame to support the wheel rakes. Such V-rakes are used to rake forage into a windrow by raking the forage from the outer edges of the implement inward. V-rakes are preferably adjustable so that the width of the windrow produced is variable and the swath raked on each pass is optimal for the circumstances encountered. For optimal operation, it is preferable that the relative angle of the wheel banks and the width of their separation be independently adjustable.
Wheel rakes are subject to repeated structural stresses due to uneven ground and irregular distribution of forage material when propelled through fields of cut hay to form the hay into windrows. The assemblies supporting the rake wheels must have considerable strength in order to bear such stresses successfully. Welded assemblies are thus preferred for their robustness and durability.
Wheel rakes convert the forward motion of the rake into a lifting and sideward motion by interaction of the rake wheels with the ground as the wheel rake is drawn forward. Compacted, damp or unusually heavy forage can create problems in that the rake wheels may tend to roll over or skip over areas of heavy compacted forage rather than lifting it and raking it toward the desired windrow. If this occurs, loss of production and increased costs result. Loss of production occurs if forage is left in the fields to decay rather than being harvested. Increased costs can occur if it is necessary to pass through the fields several times to accomplish sufficient raking to gather all of the forage desired. Thus, the efficiency of a wheel rake for lifting and moving forage can have a significant economic effect on hay farming.
Rake wheels include a plurality of tines extending from the rim of the wheel. Flexible metal tines lift and move forage to one side as the rake wheels rotate.
Traditionally, and sometimes today, tines extend the entire distance from the rake wheel hub beyond the rim. More commonly tines are attached to the wheel rim and the rim to the hub via spokes or a wheel disk. In the event that spokes are utilized, the spokes are often covered by a plastic disc. This arrangement keeps forage from passing through the wheel instead of being raked as desired.
Modern rake wheels often utilize metal tines mounted in flexible rubber bases. The rubber bases secure the tines to the wheel rim and provide a measure of controlled flexibility so that the tine can flex in response to loads in all directions without bending or breaking.
Wheel rakes are typically constructed so that multiple rake wheels are mounted side by side mounted on long beams. It is desirable that the beams be adjustable in width or separation and in the angle that the beams make with the path of travel as viewed from above. Prior wheel rakes have not allowed any adjustment of vertical raking angle.
The angle at which rake wheels contact the ground during the raking operation affects the ability of the wheel tines to lift and move forage. A more aggressive raking angle is one where the plane of the rake wheels is angled somewhat from the vertical. A less aggressive raking angle keeps the plane of the rake wheels close to vertical relative to the ground. At some times, when forage is heavy or compacted a more aggressive raking angle is desirable. At other times, conditions are such that forage left in the fields is light and not compacted. At these times, it would be valuable to be able to harvest forage with a less aggressive raking angle to minimize wear on wheel rake components.
A more aggressive raking angle allows the tines or fingers of the rake wheels to “dig in” better. That is, the tines reach under the forage to a greater degree. This greater reaching under tends to provide better lift and application of sideward force to the forage to improve the raking of heavy or compacted forage.
Thus, it would be a benefit to the agricultural arts to have access to a hay rake that allows for adjustment of raking angle to allow for ready adjustment from a less aggressive raking angle to a more aggressive raking angle.